Standardize naming of CI variables

All are now called CI_* instead of DJANGO_*, DO_* and TRAVIS_*.

Signed-off-by: Michal Čihař <michal@cihar.com>
Share code for install

Signed-off-by: Michal Čihař <michal@cihar.com>
Okay using SET NAMES is safer

Signed-off-by: Michal Čihař <michal@cihar.com>